A timeless fable tells of the journey of the tortoise to a party hosted by his friends the birds. It was journey spurred on by imagination, fueled by innovation and enabled by collaboration. The deal was that tortoise would have feathers (graciously donated by his erstwhile feathered friends) glued on with wax, and thus be the odd member of the flock, in the entourage taking on the journey to the far away party possible on by air.

Depending on the moral intended, the fable takes a number of divergent paths albeit with a common tragic end to tortoise’s journey: The sun’s heat, melting of wax and the inevitable. This, a powerful fable appealing to a universal human fantasy. Likewise, science tells us that some feat it is that the human species is bipedal.

But our imagination tells a different story. Of airborne superheroes with telling names like Superman. Of superhuman beings with ability over gravity: angels, fairy and witches. More so, in our chronicle of human history, some names shall forever be (the Wright brothers) names that dared like the tortoise.

To the list, add mordern day innovators like Bertrand Piccard and André Borschberg. 21st century thinkers who responded to the challenges of the time and unlike the tortoise flight that was disadvantaged by the sun, made good of the orb in the sky and make ‘around the world in a solar plane’ possible.

In case you are yet to get the in on the latest show and tell as far as green technology in the aviation industry goes; yet to know of the star attraction at 2011’s edition of the world’s number 1 airshow; the “special guest”as the organizers of the Paris Air show love to put it. Moran in the City obliges, in Solar Impulse HB-SIA, every reason to be excited or as Sheryl Crow puts it, soak up the sun.

The Journey t Towards Environmental Friendly Transport Aircraft

Dr Martin Hepperle of the German Aerospace Center, Institute of Aerodynamics and Flow Technology in a 2002 paper presented at the SATB symposium in Munich succinctly elaborates the journey towards environmentally friendly transport aircraft.

Acknowledging the immediate need for green technology in the aviation industry, driven primarily by rising demand for this mode of transport, Dr Hepperle asserts that the solution lies in increasing the capacity of air transport while keeping to the demands of the age- sustainability in all activities human this 21st Century.

To this end, four strategies that the aviation industry has been tinkering with

Increasing the number of aircraft,

Reducing the turn around time at the airport and separation between flights,

Enlarging the aircraft capacity,

Increasing the cruise speed of aircraft.

The first two strategies traditionally rolled out by simply expanding the fleet range via getting more of the same, expansion of airport terminals and taxi ways are akin to applying a band aid to a haemorrhaging bullet wound. Simply too little benefit at the expense of rising environmental and cost concerns. Better hope lies in the latter two which as Dr Hepperle scientifically expounds in the paper, call for a rethink in aircraft design and development of new configurations.

Acknowledging that some strides have been made ( best example being the now operational super jumbo- The A380) Dr Hepperle offers some suggestions on the way forward whilst concluding by highlighting the need of convergence and expansion of ongoing research. Sifting through the equations that Dr Hepperle uses to back the new design suggestions, it is easy to see why the Solar Impulse HB-SIA generates that much excitement.

In an April press release, it is easy to pick the eagerness of the creators of The Solar Impulse at participating at this year’s Paris Air show. Among the highlighted events are the daily flights that visitors to the century old, undoubtedly world’s number 1 airshow will witness for six days ( 20th June to 26th ) weather permitting.

As the creators of the Solar Impulse put it

“visitors to the show will be able look closely at Solar Impulse on the ground, and each morning, so long as weather conditions are favorable, admire its majestic flying displays whilst marveling at the silence of its electric motors”

The statement may appear just as good copy writing, but looking back at Dr Hepperle’s paper, some triumph for technology this Solar Impulse is. Key to the configurations for “The Green 24 Hour Aircraft “ lies in noise reduction. Less noise (-10….-20dB) form the engine and airframe both during take off and landing translates to greater 24 hour use.

Reading on the press release, the creators of the Solar Impulse offer:

” Given its 64 meter wingspan (as wide as an Airbus A340), light weight and extremely
slow speed, organizing flying displays by the Solar Impulse HB-SIA at the Paris Air
Show is also a real aviation challenge, which will be faced jointly on a daily basis by
teams from both the Show and Solar Impulse.”

Key in the above statement are the leading lines which talk of a generous wing span, light weight and extremely slow speed all key ingredients in configurations of “The Green 24 Hour Aircraft”. As far as light weight goes, thanks to advances in synthetic material engineering , carbon fiber the super material of the 21st Century has been a godsend (for lack of a better word).

Airbus American rival Boeing fronts the delay plagued Dream-liner 787 as it’s answer to the environmentally friendly A380 largely on account of its carbon fiber casing. For Solar Impulse, carbon fiber means that the prototype weighs just as much as an average family car- a paltry 1600kgs.

On account of the extremely slow speed of the Solar Impulse highlighted in the press release, answers are found in Dr Hepperle’s paper which offers the little fact that “noise scales approximately with velocity to the power of 5, it is desirable to fly as slow as possible”.

The ‘real aviation challenge’ that the press release alludes to stems from the fact that as much as slow is desirable, as Dr Hepperle points out, the challenge in configuring “The Green 24 hr aircraft lies in reducing the noise footprint as well by minimizing the time spent close to the ground during take off. To this end, the Solar Impulse wing span that is comparable to that of the A340 is of benefit in take-off aerodynamics as it contributes to lift.

Solar Impulse- Green Technology In and Out
Green technology advancements in the aviation industry have been spurred on by loud noise emanating from global discussions such as the COP 15 and subsequent ‘global warming meets’ as Cancun. Besides, studies done recently allude that the aviation industry is a major contributor to green house emissions (currently 3% expected to raise to 5% by 2050).

In response corporations like Shell and Virgin Atlantic have been on the forefront in the drive towards use of bio fuels to power commercial flights. In Solar Impulse, a new frontier opens offering hope to humanity in it’s quest to surmount 21st century c challenges.

From airline executives keen on protecting profits by limiting the reliance of the aviation industry oil to farmers in Africa whose horticultural produce faces the risk of boycott by the new age shopper in European markets thanks to labels that scream out a larger carbon footprint thanks to air haul, Solar Impulse is that ray of hope.

Thanks to 12,000 solar cells integrated to the wing power four electric motors (maximum power 10CV each) and charge 400kg lithium polymer batteries providing enough power to t run the Solar Impulse day and night without the need of fuel

Almost zero carbon emissions save for probably those inevitably produced during manufacture as with any other product

7 years, team of 70 skilled professionals backed by 80 partners to bring us the Solar Impulse